/*
 * Copyright:  2018 smarabbit studio.
 *
 *  Licensed under the Confluent Community License; you may not use this file
 *  except in compliance with the License.  You may obtain a copy of the License at
 *
 *  http://www.confluent.io/confluent-community-license
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OF ANY KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations under the License.
 *
 *  @作   者： 黄开晖 (117227773@qq.com)
 *  @日   期:  2021年8月24日
 */
package com.massyframework.beanskin.maven.plugin.util;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Arrays;

/**
 * @author huangkh
 *
 */
public abstract class NumericUtils {

	private static final String HEX_PREFIX = "0x";


	/*
	private static boolean isValidHexQuantity(String value) {
		if (value == null) {
			return false;
		}

		if (value.length() < 3) {
			return false;
		}

		if (!value.startsWith(HEX_PREFIX)) {
			return false;
		}

		// If TestRpc resolves the following issue, we can reinstate this code
		// https://github.com/ethereumjs/testrpc/issues/220
//	        if (value.length() > 3 && value.charAt(2) == '0') {
//	            return false;
//	        }

		return true;
	}
	*/

	public static String cleanHexPrefix(String input) {
		if (containsHexPrefix(input)) {
			return input.substring(2);
		} else {
			return input;
		}
	}

	public static String prependHexPrefix(String input) {
		if (!containsHexPrefix(input)) {
			return HEX_PREFIX + input;
		} else {
			return input;
		}
	}

	public static boolean containsHexPrefix(String input) {
		return input.length() > 1 && input.charAt(0) == '0' && input.charAt(1) == 'x';
	}

	public static BigInteger toBigInt(byte[] value, int offset, int length) {
		return toBigInt((Arrays.copyOfRange(value, offset, offset + length)));
	}

	public static BigInteger toBigInt(byte[] value) {
		return new BigInteger(1, value);
	}

	public static BigInteger toBigInt(String hexValue) {
		String cleanValue = cleanHexPrefix(hexValue);
		return new BigInteger(cleanValue, 16);
	}

	public static String toHexStringWithPrefix(BigInteger value) {
		return HEX_PREFIX + value.toString(16);
	}

	public static String toHexStringNoPrefix(BigInteger value) {
		return value.toString(16);
	}

	public static byte[] toBytesPadded(BigInteger value, int length) {
		byte[] result = new byte[length];
		byte[] bytes = value.toByteArray();

		int bytesLength;
		int srcOffset;
		if (bytes[0] == 0) {
			bytesLength = bytes.length - 1;
			srcOffset = 1;
		} else {
			bytesLength = bytes.length;
			srcOffset = 0;
		}

		if (bytesLength > length) {
			throw new RuntimeException("Input is too large to put in byte array of size " + length);
		}

		int destOffset = length - bytesLength;
		System.arraycopy(bytes, srcOffset, result, destOffset, bytesLength);
		return result;
	}

	public static byte[] hexStringToByteArray(String input) {
		String cleanInput = cleanHexPrefix(input);

		int len = cleanInput.length();

		if (len == 0) {
			return new byte[] {};
		}

		byte[] data;
		int startIdx;
		if (len % 2 != 0) {
			data = new byte[(len / 2) + 1];
			data[0] = (byte) Character.digit(cleanInput.charAt(0), 16);
			startIdx = 1;
		} else {
			data = new byte[len / 2];
			startIdx = 0;
		}

		for (int i = startIdx; i < len; i += 2) {
			data[(i + 1) / 2] = (byte) ((Character.digit(cleanInput.charAt(i), 16) << 4)
					+ Character.digit(cleanInput.charAt(i + 1), 16));
		}
		return data;
	}

	public static String toHexString(byte[] input, int offset, int length, boolean withPrefix) {
		StringBuilder stringBuilder = new StringBuilder();
		if (withPrefix) {
			stringBuilder.append("0x");
		}
		for (int i = offset; i < offset + length; i++) {
			stringBuilder.append(String.format("%02x", input[i] & 0xFF));
		}

		return stringBuilder.toString();
	}

	public static String toHexStringNoPrefix(byte[] input) {
		return toHexString(input, 0, input.length, false);
	}

	public static String toHexString(byte[] input) {
		return toHexString(input, 0, input.length, true);
	}

	public static byte b(int m, int n) {
		return (byte) ((m << 4) | n);
	}

	public static boolean isIntegerValue(BigDecimal value) {
		return value.signum() == 0 || value.scale() <= 0 || value.stripTrailingZeros().scale() <= 0;
	}

}
